Extension step-ladder



(No Model.)

T. W. ALEXANDER. EXTENSION STEP LADDER.

No. 589,326. Patented Aug. 31,1897.

Iva/e 12 ?or .775 eafik zZwYfi/Pranier UNITED STATES PATENT OF ICE.

THEOPHILUS \V. ALEXANDER, OF BURLINGTON, IOXV A.

EXTENSION STEP-LADDER.

SPECIFICATION forming part of Letters Patent No. 589,326, dated August31, 1897.

Application filed January 19, 1897. Serial No. 619,795. (No model.)

To all whom it may concern:

Be it known that I, THEOPHILUS WV. ALEX- ANDER, a citizen of the UnitedStates,residin g at Burlington, in the county of Des Moines and State ofIowa, have invented certain new and useful Improvements in ExtensionStep- Ladders; and I do hereby declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

' My invention relates to improvements in extension step-ladders inwhich I employ a non-extensible prop, whichis hinged or pivotallyattached in a novel manner to the stepladder proper, and theextension-ladder is arranged to be projected or withdrawn alongside ofthe step-ladder proper without adj usting or changing the prop.

The objects of my invention are, first, to provide a simple, strong, andduarble con struction which may be easily and readily adjusted forservice around a dwelling, store, on a farm, or in any other place wheresuch a structure may be desirable or necessary; secondly,to so constructand arrange the parts that the extension part when not in service willbe entirely out of the way; thirdly, to provide a novel means forconnecting the hinged prop to the main ladder and for guiding theextension-ladder in moving the same endwise on the main ladder;fourthly, to provide simple autom atic holding-dogs arranged on the mainladder to engage directly with the steps of the extension-ladder in amanner to permit the dogs to engage automatically when the extension iswithdrawn and to be thrown back out of position by a sharp pull on theextension-ladder when it is desired to retract the latter, and toimprove the structure in minor details, so as to-promote the efficiencyof the same.

With these ends in view my invention consists in the novel combinationof devices and in the construction and arrangement of parts, which willbe hereinafter fully described and claimed.

To enable others to understand my invention, I have illustrated thepreferred embodiment thereof in the accompanying drawings,

forming a part of this specification, and in which-- Figure l is aperspective View with the extension-ladder withdrawn partially from thestep-ladder proper. Fig. 2 is a side elevation with the extensionretracted. Fig. 3 is a longitudinal sectional view showing by full linesone of the holding-dogs in engagement with the extension ladder and bydotted lines showing the dog thrown back out of position. Fig. 4 is adetail perspective view of one of the slidable keepers for theextensionladder. one holding-dog. Fig. 6 is a detail view of one of thestationary keepers for guiding the ladder extension in its endwisemovement and also serving as the support for the hinged prop.

Like letters of reference denote corresponding parts in all the figuresof the drawings, referring to which A designates the step-ladder proper.B is the slidable member or the extension-ladder, and C is the hingedprop which holds the ladder in an upright position when opened forservice.

The main ladder or the step-ladder proper, A,consists of the usual siderails and the tran sverse pieces forming the steps. The slidable orextension member B is constructed of similar side rails and crossstep-pieces, but the extension member B is not as long as the mainladder A in order that the extension may be retracted within the limitsof the main ladder, so as to be entirely out of the way and notinterfere with the adjustment and service of the ladder A.

I prefer to so arrange the two members A B andfto limit the slidinginward movement of member B that the steps thereof will coincide or liein the same plane when the extension-member B is retracted its fulllimit within the main ladder A.

The extension member B has its rails fitted edgewise against the railsof the ladder A, and the two members or ladders A B are confined or heldtogether by keepers D E, which permit the member B to slide endwise onthe main member A of the step-ladder. Two of the keepers D are employednear the upper Fig. 5 is a detail perspective view of end of member A,and two keepers E are arthe two members A B, and they are fastened inany preferred way to the slidable or extension member B, so as to movetherewith when the latter is adjusted, said keepers sliding freely onthe m ain-ladder member A. The keepers D, however, are stationary andthey are constructed in a novel way to serve the twofold purpose offurnishinga guide for the extension member'B and a support for the prop0. Each stationary keeper is cast in a single piece of metal with a fiatplate d, the flanges cZcZat the end edges of the plate, and the pintle61 which projects from the back flange (1". The main stationary member Ahas the front edge of its side rails recessed at a, and the keepers Dare fitted laterally against the outside of the rails in a position tohave the flanges cl fit in the recesses a, while the rear flanges dembrace the rails of the extension member B, said keepers D beingfastened to the member A by screws or other suitable fasteners.

It will be seen that the slidable and stationary keepers embrace themembers of the ladder in a manner to confine the member B against bothedgewise and sidewise displacement; but at the same time the member B isfree, except when restrained by the holdingdogs presently described, tomove endwise on the member A. t

The pintles (1 project outward from the stationary keepers at the backof the ladder, and these pintles pass through holes in the legs of theprop O to connect the latter pivotally to the member A through themedium of the pintles and the keepers D, which are fixed to said memberA. The protruding ends of these pintles are threaded to receive the nuts0, or other retainers maybe used for the purpose of holding the prop inengagement with the stationary keepers. The prop is strengthened by thecrossed braces c and the transverse strip 0, and the outward m ovementof the prop away from the member A of the ladder is limited by the cordsC,which are fastened to the eyes or loops 0 attached to the prop and tothe main member A of the ladder.

F F designate the holding-clogs, which are pivotally attached within theside rails of the membersA and are arranged in such relation to theslidable member B as to directly engage with the steps thereofautomatically when the member B is withdrawn for use. Each dog is castin a single piece of metal with a beveled nose f and with an angular arm9, which terminates in a lip or flange h. The dog is pivoted at 2'within the ladder-rail and lies normally in an inclined position toextend well across the rails of the memberB and fit beneath the stepsthereof to afford a firm support for said member B. The arm g of eachdog extends to the front of the rails of member A in order that the lip7b thereon mayfit over the flanged end cl of the keeper D, and thus thearm and lip serve as a stop to arrest the inward movement of the dog.

It will be noted that the dogs are arranged or hung to be off balancewhen the ladderis in an upright position and. that they lie in the pathof the steps of the slidableextension member. hen the member Bis raised,its steps strike the inclined dogs,wl1ich yield or give to permit thesteps of the slidable member B to' pass the dogs, which drop back intoplace beneath the steps immediately after said steps shall have passedthe dogs, in order that the memberB may be kept from sliding back by itsown weight. The stop devices on the dogs limit the inward movement ofthe dogs and prevent them from dropping too far and allowing the memberB to slip and descend. To lower the member B, it is raised suddenly inorder to strike the dogs sharply and with sufficient force to throw thedogs forward past their center of gravity and incline them beyond thefront of the member A, thus throwing the dogs out of the path of thesteps of the member B and permitting the latter to descend withouthindrance from the dogs. After the member B has been lowered the desireddistance the dogs may be turned by hand back to their normal positions.

I prefer to brace the side rails of the extension member B by means of atie rod or bolt G, which passes through the rails and the keepers E torigidly join and strengthen the parts.

To prevent the ladder from slipping on the fioor or pavement, pointedspurs or other suitable means (not shown) may be fastened to the siderails of the main member A. of the ladder.

From the foregoing description taken in connection with the drawings itwill be noticed that my ladder may be used with the same case andfacility as ordinary step-ladders. It possesses the advantageousproperty, however, of affording an extension-ladder which may bewithdrawn for servieewithout hindrance from or interfering with thefoldable prop, and said extension is held socurely locked in place byautomatically-actin g dogs arranged to engage directly with the steps ofsaid extension-ladder section, thus simplifying the construction andpromoting the efficiency of the structure.

It is thought that the operation and advantages of my invention will bereadily understood and appreciated by those skilled in the art from theforegoing description taken in connection with the drawings.

Having thus fully described my invention, what I claim as new, anddesire to secure by Letters Patent, is

1. The combination with a main-ladder member A, and a slidable extensionmember B fitted edgewise against said member A, of the stationarykeepers D fastened to the side rails of the main member and flanged toembrace the slidable member, said keepers projecting at their rear endsbeyond the slidable extension member and provided with the integralthreaded pintles (Z which project laterally from the keepers, thenon-extensible prop O fitted loosely on the pintles and thereby attachedpivotally to the stationary keepers, nuts fitted on the threaded ends ofsaid pintles, and holding-dogs pivotedto the side rails of the mainmember and engaging with the extension member, as and for thepurposesdescribed. 7

2. The combination with the main and eX- tensible members of a ladder,and a hinged prop, of the automatic holding-dogs F arranged Within therails of the two ladder members and provided with the stop-arms gflanged to embrace the edges of the rails of the main-ladder member, forthe purpose of In testimony whereof I affix my signature 2 5 in presenceof tWo Witnesses.

THEOPHILUS XV. ALEXANDER. Witnesses:

J NO. J. SEERLEY, CHAS. O. CLARK. I

